Benjamin Flower left the journal in 1896 but returned in 1904 determined to make it "one of the great conscience forces in the English-speaking world." He added, "let us agitate, educate, organize and move forward, casting aside timidity and insisting that the Republic shall no longer lag behind in the march of progress." Flower argued that all literature should be didactic and believed that all novels and poems should have a social purpose. Flower promoted the work of novelists such as Frank Norris, David Graham Phillips and Upton Sinclair. In an article, The Highest Function of the Novel, Flower praised those writers who were "the champions of the world's helpless millions". Flower employed investigative journalist to obtain information that was part of his campaign for social, economic and political reform. In doing so, The Arena followed the example of McClure's Magazine and began to specialize in what became known as muckraking journalism.
In the early 1900s the circulation of The Arena reached over 30,000. However, the magazine was never economically successful. It lost $37,809 in its first year and although the situation improved, the journal only made an annual profit in four of the twenty years it was trading. The last edition of the magazine appeared in August, 1909.